Dear :

I am sorry I have to return the [goods] we received on [date]. They were mistakenly included in the order you delivered to our store at [address]. Please refer to the enclosed Order form (No. ).

Maybe these [goods] were destined for another customer of yours. Please let me know what to do with these goods.

I would appreciate it if you could send us a corrected invoice as soon as possible and credit our account accordingly.

Sincerely yours,

[name]

[title]